Using a brick garage as a workshop

[BaldricParticipant @baldric]

[BaldricParticipant @baldric]

I have recently moved house and will be converting a detached brick the garage for use as a workshop, this subject has been covered in some forms but I can't see for a brick garage.

Looking at the floor I need to repair it as it is uneven and some of a skim top coat that was there is breaking up, I will remove any loose or hollow sounding areas of the old skim, but then what? I was looking at something like **LINK** has anyone else used this type of material? I was looking to do this in 2 pours so that I can move my lathe from one end of the workshop to the other once the first pour has set, the first pour being up to a wooden batten.

I don't intend to put insulation/wood on the floor as I hope to get larger machines and don't want to loose much headroom.

When it comes to the wall I was looking to insulate as shown in the second image here **LINK** but instead of plasterboard on the inside I am planning to use plywood so that I can screw hooks, shelves etc. where I want in the future. It seems to me that there is a damp-proof material behind the timber uprights, additional timber to keep the insulation of the wall maintaining an ir gap then the insulation, then ply, although the text says to use a membrane if the insulation is only between the timbers, I assume before the ply where they have additional layer, would this be affected by screws? Where there are pillars in the wall there would be no insulation to create a flat wall. Does this seem reasonable?

The roof is currently corrugated sheets on timber cross members, I was planning on adding beams at 90 degrees to the current ones and insulating between these as per the walls, then finish with either thin ply or possible white hardboard.

There will be a side door replacing the current single glazed window, I plan on this being a modern insulated door, if it has glass it will be obscure. The main door is currently a pair of wooden doors, I want to still allow occasional use of these so was thinking of either adding insulation to these or creating a removable wall behind, increasing security and insulation.

Whilst this solution may not achieve the specifications for living areas does it sound a reasonable compromise between cost, comfort and space lost?

[Les Jones 1Participant @lesjones1]

Hi Baldric,
Make sure you have a damp proof membrane in the flood so you do not have an unwanted source of moisture that raises the humidity.

Les.

[BaldricParticipant @baldric]

Les,

I can't see one in the floor, there is one visible in the walls, if put a DPM on the floor then put 1-2" of screed on the floor it will be above the DPC in the wall, is this OK? What is the minimum thickness of screed I could put on a membrane? For info the current floor is about 2" above the level of the drive already, I am not sure if that is original or not.

Baldric

[Bob RodgersonParticipant @bobrodgerson97362]

Hi Baldrick,

my workshop is a single skin brick built double (tandem) garage. My previous garage workshop was also single skin brick and when we first moved in from new it let in water like a sieve. I was told that it would eventually seal itself which it did but it took about 4 years and this took it's toll on the workshop equipment.

When I moved into my current house all I had was a single garage that was made from Cement Asbestos sheet and timber. As part of the deal with SWMBO I was allowed to have a workshop built. The asbestos garage was left where it was and housed my workshop equipment until the new one was built.

Before moving the equipment into the new workshop/garage I lined the walls with insulated plasterboard 27mm thick. After putting up the plasterboard I also fitted/glued 4mm thick foam plastic from waist level down to protect the walls from scrapes from things such as motor cycle handlebars.

I have several machines and bits of equipment that have been in there since new and they show no signs of rusting and I can confidently leave things for as long as I like and there is no signs of corrosion evident.

[Les Jones 1Participant @lesjones1]

Hi Baldric,
I don't know the minimum thickness of screed you could get away with. When I built my workshop I used compacted hardcore covered with a layer of sand (To avoid the hardcore puncturing the membrane.) then the membrane then 5 or 6" of concrete. I later covered this with quarry tiles as the concrete always had a dusty surface. I do not know how you can tell if there is a damp proof membrane unless you can see it coming up between the edge of the concrete and the wall.

Les

[Bob Brown 1Participant @bobbrown1]

There are a number of self levelling compounds available, some will cope with a thicker layer than others, although they are called self levelling they only do this up to a point and still need to be worked level. If the floor slab does not have a DPM then one can be added over the self levelling compound.

Most garage floors are below the damp proof course so this needs to be taken into consideration when lining the inner walls. Should be easy to see where the DPC is as it should be visible inside or outside.

As far as the ceiling/roof is concerned do not forget to leave a air space above the insulation else you could get damp and increase the chances of rot in the timber roof structure.

Time to make a cosy workshop

Bob

[Brian WoodParticipant @brianwood45127]

Hello Baldric,

You can always drill a test hole in the floor and see what comes out, I mean a decent sized hole and look for plastic in the dust; If there is a membrane then back fill the hole with silicone sealant to restore a dpc and close with cement.

If there is no dpc then I think your best solution is to remove the old slab and re-lay it correctly, finishing below the dpc in the walls.

A white ceiling reflects light and will make it nice to work in, but I would use insulating board finished with white emulsion paint. Lots of insulation overhead and as much as you can spare in the walls before finishing as you suggest. I would also be logical over cable runs in the walls, even to marking their positions or at least take photos.before closing up. Heating might be best with a simple convection heater, wired through a thermostat and backed up with a small de-humidifier. Interwoven chain link fencing strategically placed will slow down those intending to break in, even under the roof sheets in a high risk area. I assume those are fibre cement, easily torn off by baddies.

Regards Brian.

Edited By Brian Wood on 17/05/2015 18:45:39

[frank brownParticipant @frankbrown22225]

There are masses of self levelling compounds, the one you linked to's main claim to fame seems to be that its sets so quickly. I am not sure that is you prime consideration. Please check that your floor is reasonablely horizontal, a mate of mine tried our one of these compounds in his kitchen – it all ran down into one corner!!

This would be a better place to put your questions :- http://www.diynot.com/

Frank

[Bob Brown 1Participant @bobbrown1]

Posted by Brian Wood on 17/05/2015 18:43:18:

 

If there is no dpc then I think your best solution is to remove the old slab and re-lay it correctly, finishing below the dpc in the walls.

 

Blimey! that's a lot of hard work never mind cost!

Bob

Edited By Bob Brown 1 on 17/05/2015 19:02:20

[Neil WyattModerator @neilwyatt]

Hi Baldric, your link is for a compound suitable for up to 20mm which should be more than enough for a damaged existing floor. There is another version for thicker layers, but I'd suggest keeping it thin and not raising above the DPC.

My workshop is a concrete walled garage on a concrete base, I put down a DPC then layers of dpc to stop scuffing and laid timbers across the floor at 10" spacing, I then put thick OSB on top and it has remained flat and firm (and warm and dry) ever since. If I had a much heavier lathe I would have put reinforcement under the legs.

Neil

[BazyleParticipant @bazyle]

If it might be used as a garage again (ie doors not bricked up) then there is a planning requirement in hte UK to have a slope towards the doors so that spilled petrol runs out.
If you can see then DPC on the inside then it is not linked to one in the floor therefore probably not one in the floor. It is not normal to have one for a garage as cars are waterproof. (it is in the wall still to protect the wall from damp and subsequent frost damage).

I suggest a skim to provide a smooth surface, DPC joined up to the one in the wall (I wonder if good old hot bitumen is still available) 2 in cement on top.

[duncan webster 1Participant @duncanwebster1]

I did my walls much as you second link, floor with mastic asphalt. You have to pay someone to do it, but it's very quick and very good, flat and damp proof

[EmgeeParticipant @emgee]

If the existing screed is breaking up in places I would suggest complete removal, then brush on bitumen damp proof course taking it up the walls to the existing DPC. Re-screed with Portland cement and sharp washed sand, 'polish' a finish to the screed with a steel float. Before use apply a good quality floor paint to make cleaning up a doddle.

[BaldricParticipant @baldric]

All,

Thanks for the responses so far, I will have to drill a hole to confirm if there is a DPM somewhere underneath.

I am loathed to take up the old floor unless it will take time and make a mess. I don't have anywhere else to store my tools/lathe so can really only do half the floor at a time which will be a pain. Before moving I did build a timber framed workshop on a purpose built concrete base, doing this I found I didn't have the knack to get a top screed flat, hence the thought of using a self levelling compound.

Baldric

[Bob Brown 1Participant @bobbrown1]

As it is a garage I doubt you'll find a DPM and even if you do I doubt it goes up to the DPC, that leaves you with three choices

1. Just screed the floor with a levelling compound.

2. As above but an additional surface DPM over the top of the screed with something on top of that to stop wear from foot traffic.

3. Remove the slab and start again.

My garage floor does not have a DPM and at present has not presented any problems RH has been reasonable, I have a max min RH/temp gauge to monitor the situation.

Bob

[Johnboy25Participant @johnboy25]

Hi Baldric & all…

The first question I'd ask is what age is the house possibly assuming the garage was built at the same time. That may give an idea of the building regs that it was built to if any! You mentioned that the brick work had a DPC. If the DPC is above the floor level I would expect that there is no DPC under the concrete slab. The garages that I've come across with building projects may if your lucky have a reinforcement in form of a mesh. The concrete slab I would expect to be 3" to 4" thick. When garages are converted to accommodation a DPC is installed pior to screeding or floor joists are laid on a DPM.

Just a few thoughts on the topic – I'm no expert but have a bit of practical experience – I leave the advice & consultancy to my nephew who is a Civil Engineer. I have the same problem with a single skin on brickwork badly extended with the dreaded corrugated cement asbestos roof which sweats prolifically in the winter even with no heating what's so ever. The plans for a new garage/workshop are on the drawing board or should I say the CAD system!

John

Edited By Johnboy25 on 18/05/2015 09:02:18

[martin perman 1Participant @martinperman1]

My workshop is my garage, no insulation, corrugated roofing material, I have no leaks and dont suffer from rust, I put heavy blankets over the lathe if I think it needs it, and if I dont go in there for long periods I spray WD40 over bare metal.

Martin P

[Nigel McBurney 1Participant @nigelmcburney1]

I once tried to level out a area of uneven workshop floor with a self levelling mix, probably ok for domestic work ,not very good for workshop, accidentally drop a heavy object and the surface shatters,so for economy use the self levelling com[pound ,then floor paint or a thin membrane then a layer of 19mm chip board,chip board has lasted for 20 years in my workshop used daily,recently I had to replace an area in front of my lathe where constant standing and the occasional spay of slurry from the chuck eroded the board,I used ordinary chip board. It keeps your feet warm and if you drop a precision tool or piece of work it does not get damaged,chip board will support large machine tool ok, my 1and 3/4 ton mill has sat on it since 1990. Brick walls,in heavy rain does the inner side of the wall get damp? if it does dont fit an inner lining until you can stop the rain,I built my double garage and workshop in brick to match the house the end gable wall is nine inch solid brick and faces the weather,and rain came through and even after several years it never sealed so I had the exterior wall rendered,not nice to look at but waterproof.Eventually I used the garage for storage and built a timber worshop .Now be careful with problems with vermin ,mice will get into buildings and love insulated cavities,keep all wiring surface mounted and visible if the cables go through the insulation use steel conduit. Down the road from me there was a large pitched roof double garage converted to a gym and living accomodation , it burned down last winter,completely destroyed, cause determined by fire brigade and insurers ,mice chewing through the wiring,luckily the garage was detached.

[mechman48Participant @mechman48]

Hi Baldric

See my posts.. re converting brick garage.. for your delectation, cogitation…

**LINK** ..

**LINK**

**LINK**

**LINK**

Have also posted some pics of conversion in progress in my album 'miscellaneous'… others will no doubt have differing methods of insulation, lighting, heating etc. but hopefully the above may assist you.

George.

 

Edited By mechman48 on 18/05/2015 10:45:00

[Bob Unitt 1Participant @bobunitt1]

Posted by Baldric on 17/05/2015 17:46:43:When it comes to the wall I was looking to insulate as shown in the second image here **LINK** but instead of plasterboard on the inside I am planning to use plywood so that I can screw hooks, shelves etc. where I want in the future.

 

I did this (the plywood). You can also put your electrics on the inner surface of the plywood, in trunking – which makes it much easier to move/add sockets and completely removes any possibility of drilling through a mains cable when fitting shelves etc. I got a qualified electrician to provide the supply to the building, fit a distribution panel, and put in the lights and a mains-ring at the top of the wall. I then added and wired in the sockets exactly where I needed them for each machine (I hate trailing extension leads) and the electrician came back and checked my work over for me before I switched it on.

 

Edited By Bob Unitt 1 on 18/05/2015 10:43:53

[Cornish JackParticipant @cornishjack]

Have built/converted two workshops, one from scratch, one already built, both 'prefab' concrete and corrugated roofs. In both, the floor was covered with a DPM, then 50mm polyurethane ally-backed foam, then 3/4 inch t&g chipboard flooring. Walls and ceiling also poly insulation topped with 1/2 inch plywood. Heating was a thermostat controlled Dimplex oil-filled heater and a medium sized dehumidifier. Both over-filled and over-loaded with medium weight machines (M7, D-W mill, Fobco drill etc.). No rust, and comfortable for 'working'. The second was destroyed in the N. Sea 'surge' and the replacement (double skinned block and brick, in progress) will be similarly constructed. Can recommend the method.

rgds

Bill

[Bob Brown 1Participant @bobbrown1]

Posted by Nigel McBurney 1 on 18/05/2015 10:02:43:

accidentally drop a heavy object and the surface shatters

Brick walls, in heavy rain does the inner side of the wall get damp?

If the surface shattered I would think it has laid incorrectly either dust or something else under it not allowing the compound to adhere correctly.

Bricks are porous some more than others as are the mortar joints so moisture will find its way through, even render is not a guarantee as render is porous. The trick is not to allow the moisture through to the inside face hence the use of a breathable membranes.

On our bungalow the gable end takes most of the prevailing weather and we found we had problems with damp on the inside, this was traced to a badly fitted lintel trays. When the property was built in the mid 60's they used lead as a cavity tray and over time it sagged forming a gutter not helped by blown in cavity wall insulation (hate the stuff should be banned) this allowed the water to run off the tray and soak the insulation and inner wall. All we did was tile the gable end above the windows problem solved.

Bob

[BaldricParticipant @baldric]

I haven't had a chance to do to much more investigation, other than checking that all is dry in the rain yesterday, and it is.

Regarding the floor, it is almost up to the wall DPC, about 1/2"-1/4" lower, that and considering the garage was is from the 1960s I guess the is no DPM then. If I don't fit one, but make sure the internal walls/insulation are not directly on the floor would there be much of a damp issue? How much really comes up through the floor? Taking up the current floor and laying a new one may be the ideal answer, but rather time consuming and expensive. If I paint one of the DPM pains on the floor/lower wall before adding the self levelling compound will that provide adequate protection?

Looking at the walls, I was planning on putting the electrics in surface trunking to allow for easy changes, exactly as suggested by Bob Unitt. I had thought of using ply as the finish, but seeing the price of OSB compared to this I might use OSB, looking around it seems to be OK, has anyone anything to say this is not the case?

Baldric

[pgk pgkParticipant @pgkpgk17461]

Do you need a DPM if using a damp-proof screed?

Some many years ago I decided to rip up old cork tiles in the utility room of that house. After spending an hour failing to get one off the floor i lost my temper and decided to bury the lot under a 3" screed and retile with ceramics – there was a step down into the room anyway.

OH (typically) demanded the whole job complete within 3 days. Further investigation found bare earth under a section of lino at one end of the room. I dug that down 6 inches, layed wall battens to screed from.. hand mixed some 30 wheelbarrows of concrete with x/s waterproof additive and covered the lot. 2 days later I started tiling – got told off for it taking nearly 5 days to finish the whole job (shesh!) but there was never a damp issue

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